Trixbox, Sangoma A101DE, Liberator S and RESTART messages

Hi Guys,

Looking for advice on this problem.

We're using Trixbox 2.6 with a Sangoma A101DE card. This system is connected to a Patapsco Liberator S ISDN converter (http://www.patapsco.co.uk/Products/Liberator/ISDN_Splitter_ISDN-C...). This allows us to share the E1 between the PBX, our videoconferencing IP->ISDN bridge and a desktop Polycom videoconferencing unit.

What I am seeing is a completely random disconnection of the E1 line, here seen from the system logs:

Oct 29 00:37:58 trixbox1 kernel: wanpipe1: RAI alarm is ON
Oct 29 00:37:58 trixbox1 kernel: wanpipe1: OOF alarm is ON
Oct 29 00:37:58 trixbox1 kernel: wanpipe1: E1 disconnected!
Oct 29 00:37:59 trixbox1 kernel: wanpipe1: RAI : OFF
Oct 29 00:37:59 trixbox1 kernel: wanpipe1: OOF : OFF
Oct 29 00:37:59 trixbox1 kernel: wanpipe1: AFT communications disabled! (Dev Cnt: 1 Cause: Link Down)
Oct 29 00:37:59 trixbox1 kernel: wanpipe1: Starting TDMV 1ms Timer
Oct 29 00:38:05 trixbox1 kernel: wanpipe1: E1 connected!
Oct 29 00:38:05 trixbox1 kernel: wanpipe1: AFT communications enabled!
Oct 29 00:38:05 trixbox1 kernel: wanpipe1: AFT Global TDM Intr
Oct 29 00:38:05 trixbox1 kernel: ADDRCONF(NETDEV_CHANGE): w1g1: link becomes ready
Oct 29 00:38:05 trixbox1 kernel: wanpipe1: Global TDM Ring Resync
Oct 29 00:38:05 trixbox1 kernel: wanpipe1: Card TDM Rsync Rx=0 Tx=2
Oct 29 00:38:06 trixbox1 kernel: wanpipe1: RAI alarm is OFF
Oct 29 00:38:06 trixbox1 kernel: wanpipe1: OOF alarm is OFF

Now, I've submitted all the required information to Sangoma engineers and they can't see anything wrong with the card; The cabling was replaced (it's only a 2m cable between the A101 and the Liberator). The dropouts are completely random and unrelated to system load; They happen in the middle of the day, sometimes at 2 AM, sometimes 5 times a day and sometimes it doesn't happen for a week, which is completely confusing me.
Every time it takes the line exactly 6 seconds to come back up to life. During 5 weeks of operation the above sequence of messages appears for a staggering 142 times.

What the Liberator engineers brought up from the analysis of the logs I've provided is what concerns me; (screenshot of the trace from the Liberator : http://img137.imageshack.us/img137/1030/liberatortrace.jpg ) It appears that trixbox is sending a RESTART message to the ISDN switch. . It almost seems as if the Tribox believes it’s lost the connection to the Liberator and is therefore trying to restart the link, even though it’s still connected! The Liberator responds to every RESTART with a standard RESTART ACK.

Can someone please explain where would the RESTART message come from and what could be the reason for it ? I'm in a typical "blame-game" situation at the moment, both parties saying their hardware is absolutely fine and I'm getting nowhere, while the line drops happily for a unknown reason...

Any tips would be greatly appreciated.

john